cutting off cats
naw im 19 im just trying to get opinons on it ive heard two diffrent things now. i know i have four of them i might just take the back ones out. and what about long tube headers what do they do.
Everyone is missing the technical aspect of this and just forgetting what the OX sensors do.
The OX sensors control the 'fuel' to air ratio for every cylinder everytime a cylinder fires.
If the sensors are just disconnected, the PCM reverts to a rich fuel table.
That's no good for fuel mileage.
If they are subbed with external 'foolers', the fuel stays fixed per the load and could go lean under extended wide open throttle because at about 3/4 throttle position on the TSP, the fuel control goes to the fixed fuel tables.
.
Cold starts could be affected. Reason is on cold starts the fuel is rich until the OX sensors heat to about 600° and take over fuel control.
If programmed out, the existing fuel tables are fixed and not able to vary to engine needs.
If programmed out and fuel tables altered for some compromise, engine still cannot benifit from proper fuel control, still no good for fuel mileage.
It's like tying both hands behind your back and running. If you stumble you have no way to protect you face from hitting the ground.
Removing the cats is a different thing all togather.
Do what you will but it's not very smart coming up with these ideas without knowing any background, is asking for drivability issues.
The gains in power and mileage on a stock engine are not what your hearing about.
Good luck.
The OX sensors control the 'fuel' to air ratio for every cylinder everytime a cylinder fires.
If the sensors are just disconnected, the PCM reverts to a rich fuel table.
That's no good for fuel mileage.
If they are subbed with external 'foolers', the fuel stays fixed per the load and could go lean under extended wide open throttle because at about 3/4 throttle position on the TSP, the fuel control goes to the fixed fuel tables.
.
Cold starts could be affected. Reason is on cold starts the fuel is rich until the OX sensors heat to about 600° and take over fuel control.
If programmed out, the existing fuel tables are fixed and not able to vary to engine needs.
If programmed out and fuel tables altered for some compromise, engine still cannot benifit from proper fuel control, still no good for fuel mileage.
It's like tying both hands behind your back and running. If you stumble you have no way to protect you face from hitting the ground.
Removing the cats is a different thing all togather.
Do what you will but it's not very smart coming up with these ideas without knowing any background, is asking for drivability issues.
The gains in power and mileage on a stock engine are not what your hearing about.
Good luck.
Last edited by Bluegrass; Oct 2, 2011 at 11:09 PM.
NEVER remove all 4. Your vehicle is not tuned to run this way.
Yes, -LongTubes, high flows and keep ALL your O2 sensors.
This is what works and there is NO need to re-tune with this configuration. As long as you install a good muffler to compliment, your low end should increase with , - the numbers/gains for proper set up, the 4.6L should at least net 20hp/25trq.
Yes, -LongTubes, high flows and keep ALL your O2 sensors.
This is what works and there is NO need to re-tune with this configuration. As long as you install a good muffler to compliment, your low end should increase with , - the numbers/gains for proper set up, the 4.6L should at least net 20hp/25trq.
NEVER remove all 4. Your vehicle is not tuned to run this way.
Yes, -LongTubes, high flows and keep ALL your O2 sensors.
This is what works and there is NO need to re-tune with this configuration. As long as you install a good muffler to compliment, your low end should increase with , - the numbers/gains for proper set up, the 4.6L should at least net 20hp/25trq.
Yes, -LongTubes, high flows and keep ALL your O2 sensors.
This is what works and there is NO need to re-tune with this configuration. As long as you install a good muffler to compliment, your low end should increase with , - the numbers/gains for proper set up, the 4.6L should at least net 20hp/25trq.
what happens if you just turn the o2s offand what abouth cutting the front ones off and putting pipe there and just running high flows
I guess you either did not read my reply, did not want to hear it or just plain don't want to believe about what the OX sensors are there for.
The cats are there by federal mandate of the EPA to clean the exhaust of combustion by products of CO, HC and NOX gasses as a condition to sell trucks in any state, local law or not has nothing to do with it.
The cats are there by federal mandate of the EPA to clean the exhaust of combustion by products of CO, HC and NOX gasses as a condition to sell trucks in any state, local law or not has nothing to do with it.
The point of Emissions, - to save our planet from catastrophic failure.
You mentioned Long Tube Headers, that's what I explained. Or was that missed? What do you really want to do?
You can remain within programmed parameters running just one converter per side, -an 02 emissions compliant replacement.
Don't just turn things off without knowing what you are doing. There's a purpose for the rear O2's, -more than most know or will tell you.
[QUOTE=jbrew;4691486]Where did you learn how to write? Did you read the post from Bluegrass?
The point of Emissions, - to save our planet from catastrophic failure.
You mentioned Long Tube Headers, that's what I explained. Or was that missed? What do you really want to do?
You can remain within programmed parameters running just one converter per side, -an 02 emissions compliant replacement.
Don't just turn things off without knowing what you are doing. There's a purpose for the rear O2's, -more than most know or will tell you.[/QU
thanks for all the advice.ps volcanos put a millon more of a carbon foot print then i will but thanks for all the advice ik what im going to do now
The point of Emissions, - to save our planet from catastrophic failure.
You mentioned Long Tube Headers, that's what I explained. Or was that missed? What do you really want to do?
You can remain within programmed parameters running just one converter per side, -an 02 emissions compliant replacement.
Don't just turn things off without knowing what you are doing. There's a purpose for the rear O2's, -more than most know or will tell you.[/QU
thanks for all the advice.ps volcanos put a millon more of a carbon foot print then i will but thanks for all the advice ik what im going to do now
I like how you had to capitalize the "t" for him haha. So what did he end up decided to do? Long tubes, hi flows, or just cutting them all off? I got lost when volcanoes got brought up.
Not sure what he decided..(?) Think he got side tracked. Last I heard he was following someones foot prints, then fell into a volcano? Iduno...




